This work captured the changes in black carbon (BC) emissions from tightened pollution controls in a city cluster in eastern China through a top-down approach that incorporated available ground observations, a chemistry transport model, and a multiple regression model. The uncertainty from the a priori emission input and wet deposition was evaluated to be moderate. More ground measurements with better spatiotemporal coverage were recommended for constraining BC emissions effectively.

In this work, hygroscopic properties of eight Ca- and Mg-containing salts were systematically investigated using two complementary techniques. The results largely improve our knowledge of the physicochemical properties of mineral dust and sea salt aerosols.

We present an empirical model for nitric oxide (NO) in the mesosphere (60–90 km) derived from SCIAMACHY limb scan data. Our model relates the daily (longitudinally) averaged NO number densities from SCIAMACHY as a function of geomagnetic latitude to the solar Lyman-alpha and the geomagnetic AE indices. We use a non-linear regression model, incorporating a finite and seasonally varying lifetime for the geomagnetically induced NO.

We introduced our identical systems, which were installed at three S. Korea stations, using CRDS and a drying system. The measurement uncertainty was ~ 0.11 ppm across the stations. CO2 observed in the west of S. Korea was very sensitive to East Asia (e.g., China), indicating that data include CO2 flux information from East Asia. Through long-term comparison to other East Asian stations, it was suggested that they could be affected not only by local vegetation but also by measurement quality.

OMU-based surface erythemal UV irradiance is compared with ground observations in the United States from 2005 to 2017. We reveal that the assumption of constant atmospheric conditions between OMI overpass time and local solar noon time may not fully represent the real atmosphere and the peaks of surface UV are not always at local solar noon because of cloud effects. Future geostationary satellites (e.g., TEMPO) would reduce sampling bias and improve trend analysis of surface UV estimate.

Clouds form by condensation of water vapour on aerosol particles. We showed that black carbon, a subset of particles responsible for a climate warming due to their strong light absorption and known to be insoluble in water, were able to form droplets when the humidity of the air is very slightly over 100 %. This is made possible by their acquisition of a coating made of hydrophilic material during atmospheric aging. The predictability of this process using theory was successfully tested.

VOCs play a key role in atmospheric chemistry. Emission and deposition on soil have been suggested as important sources and sinks of atmospheric trace gases. The exchange characteristics and heterogeneous chemistry of VOCs on soil, however, are not well understood. We used a newly designed differential coated-wall flow tube system to investigate the long-term variability of bidirectional air–soil exchange of 13 VOCs at ambient air conditions of an urban background site in Beijing.

Organic matter comprises a substantial proportion of the mass of toxic airborne particles which cause poor health and premature death. In this paper, new measurements of three important groups of organic compounds are reported and are analysed to infer their sources and their contributions to airborne particle concentrations.

The composition of airborne dust influences climate and ecosystems but its measurements presents a huge analytical challenge. Using online single-particle mass spectrometry, we demonstrate differences in mineralogy and mixing state can be detected in real time in both laboratory studies and ambient measurements. The results provide insights into the temporal and spatial evolution of dust properties that will be useful for aerosol–cloud interaction studies and dust cycle modelling.

We found that in wintertime Shijiazhuang fine PM was mostly from primary emissions without sufficient atmospheric aging. In addition, secondary inorganic and organic aerosol dominated in pollution events under high-RH conditions, likely due to enhanced aqueous-phase chemistry, whereas primary organic aerosol dominated in pollution events under low-RH and stagnant conditions. Our results also highlighted the importance of meteorological conditions for PM pollution in this highly polluted city.

Biogenic fluxes from soil at a local and regional scale are crucial to study air pollution and climate. Here we present field measurements of soil fluxes of nitric oxide (NO) and ammonia (NH3) observed over four different land cover types, i.e. bare soil, grassland, maize field, and forest, at an inland rural site in Benin, West Africa, during the DACCIWA field campaign in
June and July 2016.

HULIS are widely distributed in atmospheric aerosol. Their sources are rarely studied quantitatively. Biomass burning is generally accepted as a major primary source with additional secondary material formed in the atmosphere. The present study provides direct evidence that residential coal burning is also a significant source of ambient HULIS in northern China based on source measurements, ambient sampling and analysis, and apportionment with source-oriented CMAQ modeling.

Aircraft vertical profiles of black carbon (BC) aerosol from the High Canadian Arctic have shown systematic variability in different levels of the cold, stably stratified polar dome. During spring and summer, efficiencies of BC supply by transport (often from gas flaring and wildfire-affected regions) were different in the lower dome than at higher levels, as apparent from changes in mean particle size and mixing ratios with CO. Summer BC concentrations were a factor of 10 lower than in spring.

We use a global climate model to study how anthropogenic emissions of short-lived atmospheric particles in different parts of the world influence the global temperature distribution. We find that the global mean temperature change per unit emission is similar for all emission regions, and the largest temperature response is found in the Arctic no matter where the emissions occur. However, for European emissions, the temperature change per unit emission is found to depend on emission strength.

Organosulfates are ubiquitous in the atmosphere. We find that chemical transformation of IEPOX-derived organosulfates, one of the most abundant organosulfates, can generate inorganic sulfate through heterogeneous OH oxidation. The findings of this work provide new reaction pathways for recycling of inorganic and organic sulfur and may suggest that organosulfates could be reservoirs of inorganic sulfates in the atmosphere.

The present study provided information on specific glaciers over the Hindu Kush Himalayan region identified as being vulnerable to BC-induced impacts (affected by high BC-induced snow albedo reduction in addition to being sensitive to BC-induced impacts), thus impacting the downstream hydrology. The source-specific contribution to atmospheric BC aerosols by emission sources led to identifying the potential emission source, which was distinctive over south and north to 30° N.

This paper presents a new technique for retrieving aerosol optical properties using multi-wavelength and multi-pixel information over the ocean. Different from the traditional satellite aerosol retrievals conducted pixel by pixel, we derive the aerosol optical properties of multiple pixels simultaneously by adding a smoothness constraint on the spatial variation of aerosols and oceanic substances. The technique asserts that the multi-pixel scheme is conducive to aerosol retrieval over the ocean.

The tornado-scale vortex in the tropical cyclone boundary layer has been speculated in intense hurricanes. A numerical experiment is conducted using the Advanced Weather Research and Forecast model by incorporating the large-eddy simulation technique. The simulated tornado-scale vortex shows the similar features as revealed with the limited observational data. The presence of the tornado-scale vortex also leads to significant gradients in the near surface wind speed and wind gusts.

We consider the budget of turbulent kinetic energy (TKE) in stably stratified flows. TKE is generated by velocity shear, then partially converted to potential energy, but basically cascades towards very small eddies and dissipates into heat. The TKE dissipation rate is vital for comprehending and modelling turbulent flows in geophysics, astrophysics, and engineering. Until now its dependence on static stability remained unclear. We define it theoretically and validate against experimental data.

Five δD (H2O) data sets obtained from satellite observations have been evaluated using profile-to-profile and climatological comparisons. The focus is on stratospheric altitudes, but results from the upper troposphere to the lower mesosphere are also provided. There are clear quantitative differences in the δD ratio in key areas of scientific interest, resulting in difficulties drawing robust conclusions on atmospheric processes affecting the water vapour budget and distribution.

The Arctic is experiencing considerable environmental change with climate warming, illustrated by the dramatic decrease in sea-ice extent. It is important to understand both the natural and perturbed Arctic systems to gain a better understanding of how they will change in the future. This paper summarizes new insights into the relationships between Arctic aerosol particles and climate, as learned over the past five or so years by a large Canadian research consortium, NETCARE.

In this study, we use atmospheric methane concentration observations collected during an airborne campaign to compare different model-based emissions estimates from the Barnett Shale oil and natural gas production basin in Texas, USA. We find that the tracer dispersion model has a significant impact on the results because the models differ in their simulation of vertical dispersion. Additional work is needed to evaluate and improve vertical mixing in the tracer dispersion models.

We estimated how much carbon monoxide, ammonia, and nitrogen oxides were emitted in the smoke from the Fort McMurray Horse River wildfire using satellite data and air quality models. The fire emitted amounts of carbon monoxide that were similar to anthropogenic (human-caused) emissions for all of Alberta over a full year. We also estimated large amounts of ammonia and nitrogen oxides emitted from the fire. These results can be used to evaluate the performance of air quality forecasting models.

Aerosols can affect the evolution of deep convective clouds by controlling the cloud droplet number concentration. We perform a detailed analysis of the pathways of such aerosol perturbations through the cloud microphysics in numerical model simulations. By focussing on individually tracked convective cells, we can reveal consistent changes to individual process rates, such as a lifting of freezing and riming, but also major differences between the three different microphysics schemes used.

Light emission from energetic hydroxyl radical, OH*, is a prominent feature in spectra of the night sky. It is routinely used to determine the temperature of the atmosphere near 90 km. This note shows that the common practice of using only a few emission features from low rotational excitation to determine rotational temperatures does not account for the bimodality of the OH population distributions and can lead to large systematic errors.

Long-term aerosol measurements from the IMPROVE network were used to investigate the simulation of mass scattering efficiency in the GEOS-Chem chemical transport model. The simulation of mass scattering efficiency was developed to better represent observations by refining the representation of aerosol size and hygroscopicity. Simulated average mass scattering efficiency over North America increased by 16 %, with larger increases in northern regions and reductions in the southwest.

The recent cooling of the equatorial eastern Pacific Ocean occurred in conjunction with enhanced cross-equatorial southerlies associated with a strengthening of the boreal summer Hadley circulation. A combination of land surface warming and reduced static stability in the tropical tropopause layer due to stratospheric cooling is suggested to have caused the increase in the deep ascending branch of the Hadley circulation and related recent decadal change in the tropical troposphere and ocean.

New particle formation (NPF) is an important source of atmospheric aerosols. For the Mediterranean atmosphere, only few studies exist. In this study we present one of the longest series of NPF by analyzing 10 years of data from Crete, Greece. NPF took place on 27 % of the available days; it was more frequent in spring and less so in late summer. Model simulations showed that NPF in the subtropical environment may differ greatly from that in the boreal environment.

The effect of SO2 at atmospheric levels on SOA formation and its oxidation state during 2-methoxyphenol photooxidation was investigated with various inorganic seed particles. The presence of SO2 increased SOA yield and oxidation state, suggesting that the functionalization reaction should be more dominant than the oligomerization reaction. SO2 and seed particles were found to have a synergetic contribution to SOA formation. The results demonstrate the important role of SO2 in SOA formation.

This research utilizes several months of lidar measurements from the Perdigão 2017 campaign to investigate flow recirculation zones that occur at the two parallel ridges at the measurement site in Portugal. We found that recirculation occurs in over 50 % of the time when the wind direction is perpendicular to the direction of the ridges. Moreover, we show three-dimensional changes of the zones along the ridges and the implications of recirculation on wind turbines that are operating downstream.